Punching tool



Mar. 20, mm. .1,449,136

F. g. YATE$ INVENTOR.

Had a Yafas ATTORNEY Patented llflar. 2Q, T923.

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FREDERICK G. YATES, O1 "WATER-BURY, CONNECTICUT.

EUNGHING T6011.

Application filed June 27, 1922.

T0 aZZ whomizf may concern Be it known that I, FREDERICK C. TV.'\TI ZS7 a citizen of Canada, and a resident of aterburv count of New Haven. and State of Ci'znnecticut. have invent-en certain new and useful Improvements in Punching Tools of which the following is a specification.

This invention relates to punching tools, and more particularly to a center-punch or prick-punch for making indentations upon metal surface.

One object of the invention is to provide a punch of this nature, by means of which indentations of uniform depth may be obtained.

Er fur'tl'ier object is to provide simple form of punch having only a few which will not easily get out of order and wnich will be simple, and cheap to manufacture.

A further object is to provide a punching tool of the above nature which will be highly efficient and durable in use.

With these and other objects in view, there has been illustrated on the accompanying drawing several forms in which the invention may be conveniently embodied in practice.

Fig. 1 represents a side view of the as sembled punching tool, showing: in perspective, a block of metal with which the tool is to be employed.

Fig. 2 is a side sectional view of the same.

Fin. 3 is a top view of the retaining); spring); shown in detached position.

Fig. i is a side view of a modified form of tool insert. adapted to be used for upsetting the heads of rivets.

Fig. 5 is a side view of another modified form of tool insert having flat ends which are adapted to be user. as nail sets.

Fig. 6 is perspective view of a still further modified form of tool insert, having cup-shaped ends for resiliently holding pivot pins or the like preparatory to forcing them into position in clock-work or other mechanism.

Tn markingmetal surfaces in the past, it has been customary for the mechanic to hold a small punching; tool in one hand and to strike the tool a series of blows with a hammer carried in the other hand. In practice, when using this method to produce a series of marks. it was found that the indentations were not uniform, but of various sizes. Attempts have been made to manu Serial No. 571,228.

facture an instrument which would produce uniform indentations and many automatic punching tools have been devised for this purpose. These automatic punching tools. however. were necessarily of complicated and delicate constructions, and were also uite troublesome and expensive to manufacture.

By means of the present invention, a punching tool has been provided which is cheap to manufacture and which will enable a mechanic to produce uniform indentations upon the surface of a metal, This tool which may be readily operated with one hand, contains no complicated or delimechanism, but on the contrary is of s "-ple, strong rigid. and durable construclllOl'l. and practically fool-proof.

Referringnow to the drawings in which like reference numerals denote corresponding parts throughout the several views, the nume al 10 represents a hollow tubular provided with a head 11, apointed tool insert 12, and a hammer member 13 slidable on said barrel. The inner surface of the barrel 10 is threaded at 15 to receive the lower end of the head 11, and the bottom of the inner surface 14 of the barrel is preferably slightly tapered at 16 to snugly fit about tapered neck sections 17, 17 of the tool insert 12. Tf desired, the inner surface 16 may be threaded instead of tapered, in which case. the necir sections of the tool insert 12 would also be threaded. The barrel 10' may be made solid and have the striking flange and tool member formed integral therewith within the scope of the invention.

The head 11 is provided with a hollow center 18 having its upper end 19 countersunk in the form of a bell-mouth to afford a thumb-hold for the hand of the user. The outer surface of the head is provided with an enlarged cylindrical finger gripping section 20, preferably knurled. below which is an intermediate smooth cylindrical section 21. terminating in a shoulder 22. Immediately below the shoulder 22 is a short smooth section 23 of reduced diameter, and a t-hreadedsection 24: adapted to engage the threads 15 on the inside of the barrel.

As clearly shown in Fig. 2, an annular groove 23 is provided between the shoulder 22 and the barrel 10. This groove 23 is provided with a base 23, its sides being formed by the shoulder 22 of the head and the upper end 25 of the barrel. A circular ill ring or spring 26, preferably formed of resilient steel wire, is seated in the groove and normally has its ends spaced apart as shown in Fig. 3, but when compressed the ends of the spring 26 will be adjacent one another.

The sliding hammer 13 is provided witl'i a pair of interior annular grooves 2", 27

. than the ring 26 in its expanded condition. By means of this construction, the hammer may be readily forced upwardly and the spring compressed, into their initial relative locked positions.

The edges between the hammer grooves 27 and 27 andthe enlarged. flared portions 29 and 29 are chamfered thc chamfer between the groove 27 and the flared portion 29 being steeper than that between the groove 27 and the flared portion 29. .lt will. thus be seen that the hammer will b more easily released, and will strike a weaker blow in the first instance-that shown in Fig. 2--th.an in the second instancethe reverse position.

The exterior of the hammer 13 is substantially cylindrical, and is provided with end flanges 30, preferably knurled. The middle section 31 of the exterior of the hammer is smooth, and is connected to the end flanges 30 by conical portions 32.

The tool insert or worlrengaging n'iember 12, as shown in Figs. 1 and 2, isprovided with a central. anvil or flange 32 of enlarged diameter, adjoining the pair of tapered see tions 17, previously mentioned. Beyond the tapered sections 17. the tool insert is also provided with a pair of smooth sections 33 having a greater taper than the sections 1'7, and terminating in conical points 34, The points 34;, 35 are preferably of different si'zes'in order to permit indentations of different shapes to be produced. In practice, each tool will be provided with a plurality of double-ended tool inserts, so that any desired range of sizes maybe obtained.

In operation, assuming the hammer 13 to be resting on the anvil 32 ,'the hammer will be moved up along the barrel 10 as far as possible, to its initial position. In this initial position, the split ring 26 will be seated in the annular groove 27 on the inside of the hammer, and will also extend part way intot-he groove 23. The hammer 13 will thus be .held from dropping down the barrel 10.

When it is desired. to use the punch, the

operator will grasp the instrument and will push downwardly on the hammer until-the pressure on the ring 26 will cause it to contract into the groove '23 until it has completely left the groove 27. The hammer 13 will then be released, and under the contin ued force applied thereto will slide down the barrel 10, striking the flange or anvil 32 and oausing the punch point to malts an indentation'in the surface of the metal block 36. I

Bymeans of the present invention, the danger ofslippage of the tool along the surface of the metal is reduced to the minimum due to the fact that the punch point is always held against the metal surface with a strong pressure. v

While the tool insert herein illustrated is adapted for usev in prick-punching the surface of a metal, other forms of tool may be employed within the scope of the present invention. Thus the ends of the tool insert may be provided with engraving implements, or with chisels for cutting the surface of the metal, stone, or other material being operated upon.

Another important use for the present inserts invention is for upsetting the ends of rivets or for inserting pivot pins into watches or other mechanisms. In these two cases, the tool inserts employed will have cencave and cup-shaped ends respectively.

In addition, if desired. tool inserts having flat ends serving as nail sets, may be employed. With such nail sets, it may be found desirable to-magnetize the tool insert so as to cause the nails to adhere to the tool.

Figs. 4:, 5, and 6 illustrate several modified terms of tool inserts which may be employed in the punching tool. Fig. 4; repre sents a tool insert having a pair of rivet sets 35 upon its extremities. The rivet sets 35, 35 are concaved or dished in the form to be given to the rivet head. The dished end 35 is preferably flatter and of larger diameter than the end 35, so that if desired, the former may be used to start the heading of the rivet. and the latter to finish it.

Threaded cylindrical sections 36*, 36, are provided adiacent the anvil 32 and are adapted to, be screwed into corresponding threads formed in the barrel 10.

Fig. 5 discloses a tool insert having nail sets 37. 33 upon its ends. The ends of the nail sets are flat and preferably of different size so that nails, brads or taclrs of different dimensions may be operated on. .The tool insert'in this instance may be made of magnetized iron so that the iron fastenings will be held against the flat ends of the nail sets 37, 38, when the tool is lifted, and even when in an inclined or vertical position.

In Fig. 6, a tool insert is disclosed having its ends formed in the shape of cups 39, 4:0.

me ias the cups 8'9, 40, is split into three resilient prongs ll, as clearly shown on the drawing. These prongs are adapted to resiliently rip various sizes of rivets, pinions, pintles. etc, preparatory to driving them into place in clock-work or other mechanisms.

In case it is desired to reduce or increase the force of the impact, it will only be necessary to change the size or material of the SDFiIlSl' wire 26. Another iethod of varying the impact force is to employ hammers or barrels of'different lengths or weights. Still another method of varying the force of the impact is to change the angle of the chamfer between the groove 27 and the flared section. 29. or to change the diameter of said flared section 29.

It will thus be seen that by means of this invention, a simple form of punching tool has been provided which may be operated with one hand if desired, and will produce indentations, fully as uniform as more expensive types of complicated automatic punches. Yet at the same time, the present punching tool has the advantage of being constructed of relatively few parts which cannot out of order, all of the parts being easily accessible for cleaning.

lVhile there have been disclowd in this specification, one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosure, but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent, is:

1. In an instrument for producing prick marks on the surface of a metal, a body having a punch point at the lower end thereof. a tubular hammer slidable on the outside of said body for engaging the lower end of said body and causing the punch point mark the metal, and means for releasably holding said hammer at the top of said body.

2. In a metal-punching tool, a tubular barrel, a pointed punch secured in one end of said barrel, a tubular hammer slidable on the outside of said barrel and adapted to engage said pointed punch, and means for initially holding said hammer near the top of said tubular barrel yet permitting its sudden release upon the application of a predetermined pressure upon said hammer.

In a metal-punching tool, a body, a detachable double-pointed tool insert secured to the lower end of said body, said tool in sert having a. flange below said body, a tubuiar hammer slldable on the outside of said Each of body, and adapted to engage said flange for delivering an impact to the tool insert, and means for initially holding the hammer near the top of said body, said means being released upon the application of a predetermined downward pressure upon said hammer.

4. In a punching tool, a barrel, 2. head threaded into the upper end of said barrel, a shoulder on said head spaced from the end of said barrel to form a groove, a re silient ring seated in said groove, a hammer member mounted on said barrel, a tool insert, said barrel having its bottom inner surface outwardly tapered, said tool insert having a tapered portion adapted to fit in the tapered section of said barrel, said resilient ring adapted to be compressed into said groove by the downward movement of said hammer, whereby said hammer will be. released and oermitted to strike a blow upon said tool insert.

In a punching tool, a shaft having a ching point upon one end, a hammer, shaft and hammer having alined annular grooves, a spring fitting jointly within said grooves, said spring being adapted to be compressed into the shaft-groove by the downward movement of said hammer to re lease said hammer. and a stop carried by said shaft for suddenly checking the downword movement of said hammer, whereby a sharp impact will be given to the punching point.

6. In a punching tool, a shaft having a punching point at its bottom end, a groove on said shaft near its top end, a spring seated in said groove, and a hammer slid able on said shaft, said hammer having a pair of interior grooves within either of which said spring is adapted to seat in its expanded condition, said spring being adapted to be compressed into the shaftgroove by the downward movement of said hammer to release the hammer and permit said hammer to strike the punching member near the bottom of said shaft.

7. In a punching tool for marking the sur face of a metal sheet or metal block. a shaft, a tubular hammer slidable on the outside of said shaft, a spring on said shaft adapted to detachably hold said hammer from downward movement, said spring being adapted to release said hammer when said hammer has been forced downwardly to a predetermined point on said shaft, and a pointed punch member adapted to be engaged by said hammer at the bottom of said shaft.

8. In a punching tool, a tubular shaft, a double-ended tool insert secured to the bottom of said shaft, a tubular hammer slidable on the outside of said shaft, said hammer being releasably held upon said shaft, and means for releasing said hammer.

9. In a punching instrument, a shaft, a

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said body, said body having an annular groove near the top thereof, a split wire ring seated in said groove, the ends of said ring being normally spaced apart, a hammer on said body having an interior groove Within which said .ring is normally adapted to expand, said ring being compressible upon the downward movement-of said hammer on said body, to release said hammer and permit it to slide down on the body and strike a blow on the work-engaging member under the I force of gravity and the hand of the user.

11. In a punching tool, a shaft having a work-engaging member on one end thereof, said shaft having an annular groove, a spring seated in said groove, a hammer having a groove initially in alinementwiththe groove on the shaft, said spring being initially expanded to seat within said hammergroove and also topartly fill said shaftgroove to initially prevent the hammer from sliding down the shaft, said spring being contractible upon the application of downward pressure to the hammer, whereby it will be caused to completely leave the hammer-groove and permit the hammer to drop under the influence of the hand of the user and its own weight, to suddenly engage the work. i

12. In a punching tool, a pointed shaft having a stop near its bottom end, a tubular hammer adapted to slide upon said shaft, said hammer being initially locked on said shaft, a spring carried on said shaft, said hammer comprising a cylindrical tube having a pair of annular grooves on its inner surface, said grooves being adapted to be interchangeably engaged by said spring, one of said grooves being of greater diameter than the other, whereby the hammer may be reversed for varying the tension of the spring required to release said hammer, said spring being released by the application of downward pressure to said hammer whereby the hammer will suddenly slide down the shaft and engage said stop.

13. In a punching instrument, a central shaft, said shaft having a work-engaging section at one end thereof, a tubular hammer slidable on said shaft forengaging said worleengaging section, and means for detachably holdingsaid hammer at the other end of said shaft.

In testimony whereof, I have affixed my signature to this specification.

FREDERICK C. YATES. 

